Bearing material and method of making the same



. Patented Nov. 8, 1927.

more!) STATES CARL CLAUS, OE PLAINFIELD, NEW JERSEY.

BEARING MATERIAL AND METHOD OF MAKING THE SAME.

No Drawing.

This invention relates in general to compressed compositions from which bearings of various kinds are made, and it has particular reference to the type of composite bearing material which is made from a mixture of finely divided metals, of different kinds, such as those known as bearin metals, for example, copper, tin, zinc, lea antimony and aluminum and so forth.

m The selected mixture is compressed w1th a relatively high degree of pressure and then heated to a comparatively high degree of temperature, to form a consolidated coherent material of a porous character capable of absorbing lubricating oil.

The heretofore known processes by which metallic bearing materials of the above stated type have been made, have required in some instances the reduction of certain of the metallic ingredients from oxide to metallic forms during the performance of the process. In other instances certain precautions had to'be observed in order to provide an essential non-oxidizing atmosphere 5 peculiar to that process, and in all of the old processes, the ength of time required to make the product has been very long, in some instances being so great as to be practically prohibitive when the questions of cost of production and time were to be considered.

After'innumerable experiments and tests, I have discovered that a high grade eflicient metallic bearing composition of the selflubricating type, can be made in a comparatively short period of time, by using a mixture of different metals in a pure state infinely divided condition, to which graphite may or may not be added, compressing the 40 same into a consolidated coherent mass and then finishing itby subjecting it to a high degree of temperature for a few minutes time, without especially providing a non-. oxidizing atmosphere. By virtue of my improved process, I have succeeded in overcoming several of the above named drawbacks found to exist in the prior processes, and I thereby produce an efiicient product, having the desirable hardness and porosity, both of which characteristics may be varied in degree by regulating the degree of the pressure used in compressing the mixture before subjecting it to the heating step.

In accordance with my invention, I have successfully made bearing material of excellent quality and high efliciency by pro- Application filed May 28,

pressure, say from 15,000 lbs. to about 50,000

1926. Serial No. 112,404.

ceeding, for example, as follows: I take finely divided copper, tin and zinc, each in a pure state and which have been kept practically free from oxidation, and mix them intimately in any suitable manner with finely divided graphite, approximately in the proportions of parts by weight of from about 80 to about 90 parts of copper, from about 7 to 1 1 parts of tin, from about 2 to 3 parts of zinc, and from about 2 to 6 parts of graphite. The fineness of the respective ingredients may be such that they will all practically pass through a 150 mesh-screen but the fineness of the ingredients may, 0 course, be varied as desired, in order to alter by such'variation the character of the roduct, which as well known will respon to a yariation in the size of the particles of the ngredients. In some cases I omit the graphite and change the proportions of the owdered metals accordin 1y. For examp e, I may use say 88 parts by weight of copper, 10 parts by weight of tin and 2 parts by weight of zinc.' In each instance practically 1Q0'parts by weight are used in the total mixture.

A charge of the mixture is placed 'in a suitable press capable of exerting a. heavy lbs. per square inch, and a degree of pressure approximately within this range of said amounts, is exerted upon the charge in a suitable mold while the charge is in cold condition, although it may be heated during 9 compression, if preferred. This compression which is preferably applied equally from opposite points as hereinafter described, is such that the composition is formed into a relatively hard and compact mass, in which the particles are forced into strong adherence with each other and it may then be handled without risk of fracturing or mut-ilating it. The fineness of the grain or texture of'this product may be made to vary, by employing different degrees of pressure under which the compression is eifected and the porosity of the finished product after the subsequent heat treatment is likewise influenced by such variation in pressure.

Upon removing the compressed body from the press, it is then placed in a closed eontainer or box and subjected therein to a heat of from about 1400 F., to about 1500 F., for a eriod of from about ten to twent minutes, epending upon the size of the article and the character of the container in which it"is heated. The. heat causes the metals, which as before stated are in a pure state practically, to form an alloy or bronze of a porous character, and when the graphite is used it is distributed throughout the mass and .also embedded in the surfaces thereof.

The article thus treated is then removed from the heater or container, and I then submerge it in lubricating oil which it readily absorbs to the extent in some cases of from about 15 percent to percent of its bulk. Being thus saturated with oil,-

the final product has its self-lubricating quality increased and if preferred the oil treatment may be deferred until after the material has been finally pressed and sized. However, I prefer to saturate the material with the oil before it is sized in a press, as I find that the oil-soaked material is easier to work and it is not torn by the dies in.

- sizing the bearing while at the same time m being from about 25 to 50, which si'rable range in degree, and' the -specific the process of making it from pure metals.

and it is a superior product whenc'ompared with many products which are made under difierent conditions than mine. It possesses a hardness greater than many of the porous bearing bronzes or alloys now onthe market; the Brinell hardness ofprodgct 1s .a e-

gravity is fr'om about 5.31 to 6.2.

'As the mixture of pulverized. materials? which are used in making this typ ing, does-not easily flow or move on ltself e of bear.-

'wh'en eompremed with 'dies, I prefer teement, filed. October-26, 1923,

of which .the present apphcatlon. is in t e' loypressure from opposite points, as set orth in m copending ap lication for pat y i'al No. 671,032,

a continuation. By this compressing charge of granulated materials-by means of dies acting from; opposite "ends or points on the charge, I have succeeded in making the product more homogeneous in structure and more uniformly dense throughout, than in cases where such material pressure exerted at a single'point or side.

.Thisis articularl true in producingabush-' "inch in len sii,

ing or arin 0 say, more than ofan and especiall when such mch thlek.

bushing has a thin wall, saya ut ,.ofan- In finishing my improved bearing to size, I I prefer to proceed in accordance with the operations set forth in another copending application for patent of mine, filed Oct. 26, 1923, Serial No. 671,033, and wherein tubular dies co-operate with a sizing mandrel insuch a manner as to give to the bearin all of its final dimensions with accuracy, w ereby the hearing when taken from the machlne is ready for installation, without further work thereon. The present-application in arts is a continuation of said copending app ication for the sizing mechanism.

In accordance with my improved method, I have made very eflicient and satisfactory bearings from the following specific mixture of graphite and metals in a practically pure non-oxidized state and finely divided, namely; about 85 parts by weight of copper;

9 parts of tin; 2 parts of zinc and about 4;

parts of graphite, which composition after being compressed is heated, then oil treated and finally sized. By thus sizing the bush ing or bearinggto. all'of its final dimensions as to length and. diameters, in a single oper ation in which the material is drawn or moved on itself and compressed to bring its oyersize to the proper size, I am able to prov1de bearings with less work in the sizing operation than heretofore, and thereby reduce the cost of manufacture.

While I have herein given the specificingredients and their proportions incomposmg the mixture which I have herein described, my invention is not limited to the heme, but on the contrary it contemplates various changes and substitutionsin the particular ingredients and their proportions as.

being within the scope of the appended clams. In referring to the roduct as an alloy or bronze, while some 0 the products somewhat different character the physical features of which are diflicult to define.

Havlng thus describedmy invention, what I zlalm and desire to secure byLetters Paten 1s 1. The method of making bearlng material, which consists in intimately mixing together finely divided copper, t1n,' z1nc and graphite with the copper argely in excess of the other three ingredients taken together, the metals being practically free from oxidation, then compressing .from opposing directions the mixture into a maybe of that'character, others may be of a self-lubricating I 7 relatively hard consolidated body, then p1acing it'in a closed container; and hea 2, Themethod of making f E- 'b ing ,material, ,which consists mately, together finely divided 'per',t1n, zinc and gra hite withthe epppcg geatly in execs of e other threomgreit from about 1400 toiabout 1500 F..- for ais-acted upon by tin; 2 parts zinc and 4 parts messes posing directions the mixture with a pressure of from about 15,000 to 50,000 pounds per sq. in., then' placing the compressed material in a closed container and subjecting it to a heat of from about 1400 to about 1500 F. for a period of from about ten to twenty minutes.

3. The method of making self-lubricating bearing material, which consists in mixing together finely divided copper, tin, zinc and graphite, in the proportions of approximately 85 parts by weight of copper; 9 parts aphite, then compressin from opposing irections the mixture wit a ressure of from about 15,000 to 50,000poun per sq. in., then placing the compressed material in a closed container and subjecting it to a heat' of from about 1400 to about 1500 F., for a period of from about ten to twenty minutes.

4. The method of producingibearing compositions which comprises t e mixing of purely divided copper 85 parts, tin 9 parts, zinc 2 parts and iraphite 4 parts, compressing the mixture y pressure up lied from opposite directions into the desired form, heating the formed material to 1400 to 1500 F. for 10 to 20 minutes.

Signed at borough of Middlesex in the county of Middlesex, and State of New J er sey, this 26th day of May, 1926.

CARL CLAUS. 

